1. Field of the Invention
This invention relates to a wire drum window regulator mounted on a door inner panel of a vehicle to raise and lower a glass window of the vehicle.
2. Description of the Related Art
Window regulators are mounted on the door inner panels of vehicles to raise and lower their glass windows. A conventional wire drum window regulator generally comprises a guide rail extending in the vertical direction (or in the direction of movement of the glass window), upper and lower pulleys rotatably attached to the guide rail at the upper and lower ends thereof, a driving motor, a drum which is turned forward and backward by the driving motor, a wire which is wound around the drum, the upper pulley, and the lower pulley, and a slider which is affixed to the wire and attached to the bottom of the glass window and slides along the guide rail (see Japanese Patent Application Laid-Open No. 2002-266553).
In the above wire drum window regulator, the guide rail with its upper pulley, lower pulley and slider (or the guide rail assembly) is first secured to the door inner panel by four-point attachment. Next, a drum base assembly (driving assembly) in which the driving motor and the drum are integrally mounted is directly secured to the door inner panel by three-point attachment. The wire wound around the drum is then engaged with the pulleys and the glass window is attached to the slider.
The installation of a conventional wire drum window regulator as described above is inefficient because the work requires many steps. In addition, the drum base assembly is installed laterally adjacent to the guide rail assembly with a clearance left between the drum and the guide rail, but the attachment of the guide rail assembly to the door inner panel is performed separately from the attachment of the drum base assembly to the door inner panel. The positional relationship between the guide rail assembly and the drum base assembly is accordingly undetermined, making the mounting work difficult.
Because the positional relationship of the guide rail assembly and the drum base assembly is undetermined as described above, a slight slack is allowed in the wire to facilitate the mounting work. However, the wire needs to be tensioned upon completion of the mounting work. Therefore, an outer tube through which the wire is passed and a spring by which the outer tube is bent to place the wire under tension become necessary. Another problem is that, since the drum base assembly is attached to the door inner panel, the vibration of the driving motor is transferred directly to the door inner panel, becoming a source of noise.